Even if used only at night, each air-conditioner costs a lot.
You can reduce this expenditure by nearly 30% merely by switching to Fenesta products. Fenesta products are made of UPVC which is a
poor conductor of heat. Fenesta UPVC windows and Doors do not allow external heat to affect the indoor temperature. Check out http://www.fenesta.com/homeowners/cut-air-conditioning-costs.aspx for more information.
